Electrochemical performance of La0.9Sr0.1Co0.8Ni0.2O3−δ–Ce0.8Sm0.2O1.9 composite cathode for solid oxide fuel cells

The mixed ionic and electronic conductors (MIEC) of La0.9Sr0.1Co0.8Ni0.2O3−δ (LSCN)–Ce0.8Sm0.2O1.9 (SDC) were investigated for potential application as a cathode material for solid oxide fuel cells (SOFCs) based on a SDC electrolyte. Electrochemical impedance spectroscopy (EIS) technique was performed over the temperature range of 600–850 °C to determine the cathode polarization resistance, which is represented by area specific resistance (ASR). This study systematically investigated the exchange current densities (i0) for oxygen reduction reaction (ORR), determined from the EIS data and high-field cyclic voltammetry. The 70LSCN–30SDC composite cathode revealed a high exchange current density (i0) value of 297.6 mA/cm2 at 800 °C determined by high-field technique. This suggested that the triple phase boundary (TPB) may spread over more surface of this composite cathode and revealing a high catalytically active surface area. The activation energies (Ea) of ORR determined from the slope of Arrhenius plots for EIS and high-field techniques are 96.9 kJ mol−1 and 90.4 kJ mol−1, respectively.